Antenna switching device



ug- 0, 1949. R. E. KESTER ANTENNA SWITCHING DEVICE s sneaks-sheet 1 Filed Aug. 2, 1945 FIQZ INVENTOR ROBERT E. KESTER m1, ATTORNEY 1949. R. E. KESTER 2,480,140

ANTENNA SWITCHING DEVICE Filed Aug. 2, 1945 3 Sheets-Sheet 2 POWER SOCKET INVENTOR ROBERT E. KESTER BY No.9 FlG .IO VflALeP-QmQ/w ATTORNEY Aug. 30, 1949 R. E. KESTER 2,480,140

' ANTENNA SWITCHING DEVICE I Filed Aug. 2, 1945 s Sheets-Sheet s INVENTOIR ROBERT E. KESTER.

ATTORNEY r H 1: i 7 2,480,140

= scribed;

impedance-matching characteristics.

Patented Aug. 30, 1949 ATENT o F E ANTEN A. SWITCHING DEVICE RobertE. Kester, Dayton, Ohio, assignor to the United States of America as represented by the Secretary of War Application August 2, 1945, Serial No. 608,567

.. V 2Claims. (Cl.-17844-) g (iGranted under the act of March 3, 1883, as

Theinvention.described herein may be manu- .factured and used by o'rlfor theGovernment for governmental purposes, j without the payment to me of any royalty thereon. r

The present invention relates to antenna ,switches and particularly switches employed in :radio. direction finding systems for. aircrafts,

bcats, et c., One suchfsystem is described in a co pendin-g application of Robert J. Kemper,

Serial No 601,274, filedJune. 23, 1945 for Wide band homing system,.wherein appair of quarter wave antennaeare placed side-by-side, spaced 2. .short distance apart and a. coaxialphasin cable connectsthem at theirbase- A half wave section of coaxial cableals extends from the base of each antennato aswitching device which forms the subject matter of the invention herein de- B wiah i. out oi the circuit of the common conductor leading to a.radio receiver, asequence of signals .reaches the receiver'whi ch may be of equal or unequal intensity, depending on the angle which one bi antennae alternately amended April 30, 1928; 370 0. G. 757) mechanism and consequent instability of the system Especiallywherea' rotary: capacitor audio modulator is employed, these speed variations produce such pronounced variations or ,wows that the signals tend to become confusingly similar.

In order to utilize the 'advantagesof such a homing system to the fullest extent, homing must be accomplished on any type of available radio frequency signals such as continuous wave hereafter referred to asC. W., modulated C. or

pulsed. Where only a C. W. radio'frequencys sig- .nal is being received, forinstancelocal modulation of the signals is necessary. to utilize normal head-phone. right-left flying procedures. Local modulation maybe derivedthrough a high speed ,rotary capacitor suchasthat described in the the common plane of the antennae forms with a.

'straightlinepointing from the antennae to the distant beacon. Such a system results in directional signals indicating the heading of the vehicle with-respect to the beacon, as will bereadily understood by reference to said Kemperapplication.

For antenna switching purposes conventional types of switches have proven ineffectual for use at very high frequencies because of their conventional make-break construction, and lack of A suitable coaxial switch construction for: use

in such a system at very high frequencies such as above the 100 megacyclerangeis described in a co-pending application of Henry R. Smith, Serial No. 603,393 filed July 5, 1945, for Coaxial switch, issued as PatentNumber 2 1251110, August 5,1947.

This type of switch is incorporated in thepresent switchingunit and makes possible the maintenance at all timesof a, continuous. connection between either one ,orthe other of the antennae and the receiver because of the overlap sequence of the swinging described in said application.

Common switch-actuating mechanisms for automaticallyactuating the pole ofa two-way or double throw switch utilizing rotary cam I and spring returnedlever devices have also been found. to be unsatisfactory because of the unequal loading of the actuatingjmoto'r' during'the rise and fallcycles of the cam lobes. Thisunequal loading causes speedjvariations throughout the switch system and Y which and serviced.

Kemper application above referred to. :The ca- :Pacitor, however, must rotate, at the very high speed of lOto 12 thousand revolutions per minute in order to-produce the desirable audio modulation tone on the incoming switched or keyedsignals. In contrast to this, the keying or switching of the antennae is accomplished at the much slower rate of about .150 switching cycles per minute.- 1' r l 7 Speed reductionirom. the speed-of the-rotary capacitor to the slower speed at which the switch is oscillated is herein, accomplished through a double reductionv trainaof. gearing, andis so arranged that asingle motor serves both to drive ca tor a d a cam which oscillates. the vswitchlever. H 7

.sincethe high speed of the motor t c set up inductive interference in the received signals,

it is necessary to properly spacethe capacitor from the motor to avoidmutual capacitance between them, and to mechanically connect the rotating shafts -by, proper flexible' dielectric couplin gs, and which permit easy removal of the vmotor if necessary.

Accordingly an Object. of the invention is-to .provide a light, portable, self-contained,- self- Another object is to provide a highly efficient and compact antenna switching and audio modulating unit, which is simple in character, designed for manufacture by mass production technique and which will operate accurately and efficiently over long periods of use and under diverse operating conditions.

These and other objects will appear throughout the specification and will be particularly:

pointed out in the claims. V

For a better understanding of the invention,

reference is had to the following description,

taken in connection with the accompanying drawings wherein Fig. 1 is an interior bottom View of the switch unit of th invention;

Fig. 2 is a side sectional view of the switch unit shown in Fig. 1, the section 2-2 of Fig. 1;

Fig. 3 is an end view of the switch unit, partly in section, showing the arrangement of the switch contacts; 1

Fig. 4 is 'a side elevation 50f the switch unit sectionally-r'shown in Fig.2;

Fig. is a fragmentary, sectional rear view of the speed-reduction transmission of the switching unit; 1

6 is a fragmentary sectional elevation of the double periphery cam drive assembly;

Fig. 7 is a top =plan"view of the switching unit with the lever coinpartment cover removed-as in Figi to show the interrelation of the switch pole, switch lever, and cam;

I Fig. 8 is a right end view of the cam end of the switch lever showing the pallet arrangement efthe lever and theidouble periphery cam.

Referring more particularly to Figs. 1, 2, and 3, "the entire switch is arranged in a housing I together with the p'ole actuating mechanism.

The housing It is illustrated as having 'apair =of horizontally -'oppo'sed bored secti'ons H and 1 2 and an intermediate, vertically disposed, bored section 13. Each of the bored sections is provided with a diametrically uniform -tubular dielectric element 14, and 4 6, respectively, for retention pf th switch contact member's H, 1 8 and FIG, respectively, and are made preferably of -pol-ystyrene material. :For convenience, the dielectric elements l tanzi 15, inserted in the horizontally bored sections H and ll, are combined into a single piece, and an ripening extends transversely of its-axis to perm-it bifurcated legs and 24 {of a "switch ipole l9 0f which they form a part, to extend therethrough. It will be understoodthererare, that the-horizontal and verticaLswitch-c'ontacts are eifectively arranged in T fashion, with the resilient le'gs 2'0 and 21 of the-switchpole 19 extending beyond the horizontal die'lectric members 1'4 and |5 and the surface of the housing It through opening 2 2. The projecting portions of legs 20 and II are suitably actuated by a reciprocable lever 23 so that overlapping switchingcycles :a re achieved. Properadiustment of studs 24 and -25 on lever '23 by increasing ordecreas'ing the :gap width between the two 'legsfzn and 2 will :provide the desired amount of switching overlap. That is, one contact may be made t'o 'openat the instant the opriosite contact is closed, -or it may be'mad'e *to open before or afterthe other closes.

Referring now to Figs. '1, 3, and "7, lever 23 is illustrated as being pivoted on a'stud "26 at-- t'ache'd to the switch housing f0. 'Adoubl'ep'eripher-y, 'follower ty e cam driven by a suitable motor 28 through reduction gearing "30 to '35, inclusive, oscillates lever-23. Motor 28 is secured being taken along line 4 to the switch housing ID, with its drive shaft 29 extending through the mounting wall of the housing l0 into a chamber 36 effectively forming a gear housing. The worm 30, mounted on the 5 motor shaft 29, is in driving engagement with worm gear 3| pinned to countershaft 32, also carrying the worm 33 in driving engagement with the worm gear 34 pinned to the cam shaft 35, which shaft has pinned thereon the cam 21 for actuating the switch lever 23. 'Thecam'zl, shown in detail in Figs. 4, 6, 7 and 8, is provided with separate cam peripheries 31 and 38, each provided with lever-actuating cam lobes 4i cooperating with respective pallets or cars 39 and 40 on thelever 21 to sequentially cycle the oscillations of switch lever 23 in predetermined signal cycles, such for instance, as the two short and a long interval of the Morse code letter U o'nj'one cam periphery, and a long and two short intervals or "the Morse code letter D, these letters preferably beingchosen because they form j'acomplemerftary-signal patternover the two cam surfaces, as is more fully described in said copend-ingapplication of Kemper-Serial No. 150L274. When cam 21 is rotated through the gearing 33 35 by motor 2'8, a-ca-m lobe =41 -on one cam periphery 31, for instance, actuates the lever 2'3 in one direction, and the 'lever '23 is caused to return-in theoppositedireetion by a succeeding lobe 41 on the oth'en'cam periphery -38'. will be understood from the above description, the oscillations of lever 23 will =alternately' break first onec'ircu'it between oneleg 2! of "the switch pole i9 andits switch contact 18, and then th'e circuit of the other leg 20 with its contact l1; the'variableam'ountpf -lost-motion allowed by the spacing between studs 2'4 =and' 25 "permitting the desireddegree of overlap switching. V For convenience, the switch contacts H, 1'3, 1'9 i0 are provided with female' type extensions 12, so "that common male type coaxial plug connectors "may be '-removably=secured to the switch, the left connector '42 and right connector #24 serving to connect the switch "contacts I and I8 to a .5 Fpair bfantennae (not shown), and the center conductor 'd-'4 serving to connect the switch to a receiver. After the switch parts are assembled fwi'thin the b'ored sections of the housing H], the openings are sealed'by plugs-lf5 and which are -threaded to facilitate *rem'ovalof the contacts for replacement due to wear. 4 The polysty-r'e'ne tubular-dielectric members l4, "(5 and 16 are provid'ed with perforations 48 'for insertion of the threaded shanks of the-contact extens'io'n members P2, which are'threaded into respective contact members n, i8, and 19 therefby forming a*continuous electrical-circuit, "'Fncse exten'sion members are likewise uniformly and continuous'ly encased within dielectric retainers co l-1.

"Fig. 5"illu'strates in-deta'il the method of reducing the speed of the =motor through=the double reduc'tion'worm gearing. 'Motors'haftZQhas pinned thereon the worm 30 which meshes with worm U5 gear 3-! the "latter being pinned on c'oun'tersh'ait '32. "-Countershaft 32 has pinned thereon a spacing collar-52 totake up side thrust against bronze bearing member'53 in Whi'chthe countershaft 32 *is' journalled. (k ller '51 on worm 'gear'33 serves as an anchoring surface through which to "insert ;a pin 55 forassembling gear '33 to shaft 32 and lserves also as athrus't'mem'ber against bronze bearing '54 similar to collar 52, on the opposite end ofjsha'ft 32. To facilit'atefremoval or replacemerit of .the 'cOuntershaJft assembly, housing [a i provided with bearing retaining bosses 56 and 55 to retain the bearings 53 and 54 respectively. The bosses are bored through to provide openings on the opposite walls of housing I0 and the openings are covered by cover cap 51 and screw plug 58. Felt wick 59 is provided for feeding lubrication to shaft 32 and bearing 53.

It will be understood that induction coil 60 together with capacitor 6 I (see Figs. 1 and 2) form the local modulating unit for superimposing tone modulation on the received signals. The rotary capacitor shown in Figs. 1 and 2, the function of which is fully described in said Kemper application, is composed of a stationary or field housing El and a rotor 62. The rotor 62 is pinned to its shaft 63. A flexible coupling member 64, preferably of rubber or other insulating material, couples rotor shaft 63 with motor shaft 29 so that motor 28 drives rotor 62 directly at its own speed of rotation, about 12,000 revolutions per minute, to impart the proper audio modulation tone on the received signals through coil 60 and connector 42.

The rotor 62 is made of solid construction to withstand the centrifugal force due to the high rotative speed. It is formed preferably of some molded plastic dielectric material, as, for example, phenol formaldehyde. The details of construction of the rotor and stator of the rotary capacitor are shown in Figs. 9, and 11. outer surface of the rotor body is provided with diametrically opposite metallized conducting areas 12, Figs. 9 and 10. Additional metallized surfaces 13 are provided at each of the rotor to form a low impedance connection between the metallized surfaces 12. The stator is provided with diametrically opposite surfaces :65, Fig. 11 on the inner surface of the stator body 6| to match the external metallized surfaces 12 of the rotor. Terminals 10 and II are brought out from the stator surfaces and connected to ground and inductance coil 60 respectively as shown in Figs. 1 and 2. The electrically conducting metallized surfaces may be applied to the dielectric material of the rotor and stator in any suitable manner, as by spraying or electroplating, such that it will have sufficient adhesive power to withstand windage and centrifugal force. The rotor revolves within the stator with a small clearance between corresponding metallized surfaces thus forming a capacitor whose capacity varies from maximum to minimum during each half revolution and provides the desired tone modulation.

In operation, motor 28 through its shaft 29, flexible coupling 64 and rotor shaft 63 drives rotor 62 directly. Through worm gear 30, gear 3|, countershaft 32, worm 33, gear 34 and camshaft 35, cam 21 is driven at a much slower speed. Rotating cam 21 oscillates lever 23 thereby switching switch pole members and 21 with respect to contact members I! and [8.

Thus a unitary device is provided which may be attached to any receiver in circuit with a pair of cardioidal field pattern homing antennae for directional homing purposes. The construction and arrangement of parts is such that the strength of incoming signals will be attenuated The at a minimum and the device may be inserted in the circuit of the receiver at a remote point on the vehicle to avoid local noise interference. Likewise, the spacing and arrangement of the capacitor with respect to the motor is such that motor noise is effectively shielded from the switch circuit.

While the invention has been shown and described in its preferred embodiment, it is anticipated that changes in the details thereof may be made without departing from the spirit or scope of the invention as claimed.

Having thus described the invention, what is claimed is:

1. A radio high frequency switching device for use in a switched-antenna direction-finding radio system, comprising a motor, a switch housing supporting said motor, speed-reduction power transmission means in said housing and actuated by said motor, said transmission means including a reduced speed shaft, a rotary capacitor having a high speed rotor mounted in said housing, a flexible drive coupling inserted between the drive shaft of said motor and of the shaft of said rotary capacitor for driving the capacitor rotor at the speed of the motor, a double periphery cam mounted on said reduced speed shaft, said cam having lobes arranged on its double peripheries in a predetermined sequence, a lever pivoted on said housing and positively oscillated by said cam whereby said lever is positively oscillated in opposite directions, and a double throw pole switch mounted on said housing, the pole thereof being mounted to be oppositely thrown in accordance with the oscillations of said lever.

2'. A radio high frequency switching device for use in a switched-antenna direction-finding radio system, comprising a motor, a housing supporting said motor, a rotary capacitor having a high speed rotor, power transmission drive means having fast and slow speed shafts mounted in said housing, said fast speed shaft driving the rotor of said rotary capacitor at the speed of said motor so that said rotor provides fly-wheel speed stabilization of said drive means and said slow speed shaft having associated therewith a lever actuating cam, a coaxial switch including a double throw pole and a switch lever pivotally mounted on said housing, said lever being formed of a light dielectric material and yoked at opposite ends to straddle said actuating cam at one end and said switch pole at the opposite end.

ROBERT E. KESTER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,204,050 Purington June 11, 1940 2,294,103 Ottenthal Aug. 25, 1942 2,310,695 Higgins Feb. 9, 1943 

